RESUMO
Viral concentrates (VCs), containing bioinformative DNA and proteins, have been used to study viral diversity, viral metagenomics and virus-host interactions in natural ecosystems. Besides viruses, VCs also contain many noncellular biological components including diverse functional proteins. Here, we used a shotgun proteomic approach to characterize the proteins of VCs collected from the oligotrophic deep chlorophyll maximum (DCM) of the South China Sea. Proteins of viruses infecting picophytoplankton, that is, cyanobacteria and prasinophytes, and heterotrophic bacterioplankton, such as SAR11 and SAR116, dominated the viral proteome. Almost no proteins from RNA viruses or known gene transfer agents were detected, suggesting that they were not abundant at the sampling site. Remarkably, nonviral proteins made up about two thirds of VC proteins, including overwhelmingly abundant periplasmic transporters for nutrient acquisition and proteins for diverse cellular processes, that is, translation, energy metabolism and one carbon metabolism. Interestingly, three 56 kDa selenium-binding proteins putatively involved in peroxide reduction from gammaproteobacteria were abundant in the VCs, suggesting active removal of peroxide compounds at DCM. Our study demonstrated that metaproteomics provides a valuable avenue to explore the diversity and structure of the viral community and also the pivotal biological functions affiliated with microbes in the natural environment.
Assuntos
Proteínas Periplásmicas/isolamento & purificação , Água do Mar/virologia , Proteínas Virais/isolamento & purificação , Bactérias/virologia , Proteínas de Bactérias/isolamento & purificação , Clorofila , Cianobactérias/virologia , Gammaproteobacteria/metabolismo , Oceanos e Mares , Plâncton/virologia , Proteômica , Água do Mar/microbiologia , Proteínas de Ligação a Selênio/isolamento & purificaçãoRESUMO
Alexandrium is a neurotoxin-producing dinoflagellate genus resulting in paralytic shellfish poisonings around the world. However, little is known about the toxin biosynthesis mechanism in Alexandrium. This study compared protein profiles of A. catenella collected at different toxin biosynthesis stages (non-toxin synthesis, initial toxin synthesis and toxin synthesizing) coupled with the cell cycle, and identified differentially expressed proteins using 2-DE and MALDI-TOF-TOF mass spectrometry. The results showed that toxin biosynthesis of A. catenella occurred within a defined time frame in the G1 phase of the cell cycle. Proteomic analysis indicated that 102 protein spots altered significantly in abundance (P < 0.05), and 53 proteins were identified using database searching. These proteins were involved in a variety of biological processes, i.e., protein modification and biosynthesis, metabolism, cell division, oxidative stress, transport, signal transduction, and translation. Among them, nine proteins with known functions in paralytic shellfish toxin-producing cyanobacteria, i.e., methionine S-adenosyltransferase, chloroplast ferredoxin-NADP+ reductase, S-adenosylhomocysteinase, adenosylhomocysteinase, ornithine carbamoyltransferase, inorganic pyrophosphatase, sulfotransferase (similar to), alcohol dehydrogenase and arginine deiminase, varied significantly at different toxin biosynthesis stages and formed an interaction network, indicating that they might be involved in toxin biosynthesis in A. catenella. This study is the first step in the dissection of the behavior of the A. catenella proteome during different toxin biosynthesis stages and provides new insights into toxin biosynthesis in dinoflagellates.
Assuntos
Dinoflagellida/metabolismo , Toxinas Marinhas/biossíntese , Proteínas/metabolismo , Proteoma/metabolismo , Dinoflagellida/genética , Fase G1/efeitos dos fármacos , Toxinas Marinhas/genética , Toxinas Marinhas/metabolismo , Proteínas/genética , Proteoma/genética , Proteômica/métodos , Intoxicação por Frutos do Mar/etiologiaRESUMO
From March 2008 to February 2009, PM(10) samples were collected and analyzed for polycyclic aromatic hydrocarbons (PAHs) at eight sampling sites in Great Xiamen Bay, China. Analyses of the seasonal and spatial variations of these compounds revealed the following results. Significantly high levels of PAHs were found in the winter compared to the summer, sometimes exceeding 100 ng m(-3), and the spatial variations were influenced most by the sampling site surroundings. Composition profiles of PAHs of an urban and a rural site were shown to be very similar with a positive correlation coefficient larger than 0.9 at the 0.01 level of significance for the same season. Diagnostic ratios, together with principal component and multiple linear regression analysis, showed that more PAHs were from grass/wood/coal combustion in winter than in other seasons. The ratios of benzo[a]pyrene to benzo[e]pyrene (BaP-BeP) in winter and fall were 0.6-1.7 times higher than those in spring and summer, suggesting the importance of local emissions of PAHs. The BaP-BeP ratios in Kinmen were generally lower than those in Xiamen, indicating that the aging degree of PAHs was higher in Kinmen than in Xiamen. The external input of PAHs from upwind urban and industrial areas was one of the key factors causing high levels of PAHs in PM(10) in Great Xiamen Bay in winter.
Assuntos
Poluentes Atmosféricos/análise , Benzopirenos/análise , Poluição do Ar/estatística & dados numéricos , Baías , Benzo(a)pireno/análise , China , Monitoramento Ambiental , Material Particulado/análise , Estações do AnoRESUMO
The cell wall is an important subcellular component of dinoflagellate cells with regard to various aspects of cell surface-associated ecophysiology, but the full range of cell wall proteins (CWPs) and their functions remain to be elucidated. This study identified and characterized CWPs of a toxic dinoflagellate, Alexandrium catenella, using a combination of 2D fluorescence difference gel electrophoresis (DIGE) and MALDI TOF-TOF mass spectrometry approaches. Using sequential extraction and temperature shock methods, sequentially extracted CWPs and protoplast proteins, respectively, were separated from A. catenella. From the comparison between sequentially extracted CWPs labeled with Cy3 and protoplast proteins labeled with Cy5, 120 CWPs were confidently identified in the 2D DIGE gel. These proteins gave positive identification of protein orthologues in the protein database using de novo sequence analysis and homology-based search. The majority of the prominent CWPs identified were hypothetical or putative proteins with unknown function or no annotation, while cell wall modification enzymes, cell wall structural proteins, transporter/binding proteins, and signaling and defense proteins were tentatively identified in agreement with the expected role of the extracellular matrix in cell physiology. This work represents the first attempt to investigate dinoflagellate CWPs and provides a potential tool for future comprehensive characterization of dinoflagellate CWPs and elucidation of their physiological functions.
RESUMO
This study developed a multilayered, gel-based, and underivatized strategy for de novo protein sequence analysis of unsequenced dinoflagellates using a MALDI-TOF/TOF mass spectrometer with the assistance of DeNovo Explorer software. MASCOT was applied as the first layer screen to identify either known or unknown proteins sharing identical peptides presented in a database. Once the confident identifications were removed after searching against the NCBInr database, the remainder was searched against the dinoflagellate expressed sequence tag database. In the last layer, those borderline and nonconfident hits were further subjected to de novo interpretation using DeNovo Explorer software. The de novo sequences passing a reliability filter were subsequently submitted to nonredundant MS-BLAST search. Using this layer identification method, 216 protein spots representing 158 unique proteins out of 220 selected protein spots from Alexandrium tamarense, a dinoflagellate with unsequenced genome, were confidently or tentatively identified by database searching. These proteins were involved in various intracellular physiological activities. This study is the first effort to develop a completely automated approach to identify proteins from unsequenced dinoflagellate databases and establishes a preliminary protein database for various physiological studies of dinoflagellates in the future.
RESUMO
The fluorescent components and their distribution and variation of dissolved organic matter (DOM) were examined using excitation emission matrix fluorescence spectroscopy-parallel factor analysis technique (EEMs-PARAFAC) for samples collected during June, 2008 from Minjiang River, a typical subtropical reservoir-type river ecosystem. Three separate fluorescent components were identified by PARAFAC, including two dominant humic-like components (C1: < 250, 325/424 nm; C2: 270, 395/482 nm) and one protein-like component (C3: < 250, 280/358 nm), of which humic-like components were dominant. Fluorescence analysis provided a 'fingerprint' technique to trace the mixing of DOM between three tributaries in the upstream of Minjiang River. The nearly constant concentration and composition in the main stream of Minjiang River reflected the effect of dam construction Correlation and principal component analysis (PCA) revealed that humic-like components were principally derived from flushing of watershed soils, while protein-like component was formed from in-situ production which could be used as a proxy of the concentration of total dissolved nitrogen (TDN). Multi-linear regression of fluorescent components C2 and C3 can be used to trace the variation of dissolved organic carbon (DOC) concentration. This study demonstrates that Minjiang is a typical subtropical reservoir-type river which still keeps relatively 'unpolluted' aquatic environment.
Assuntos
Compostos Orgânicos/análise , Rios/química , Espectrometria de Fluorescência/métodos , Análise FatorialRESUMO
This Technical Note is the first description of a large-scale logarithmic flow-rate damping system designed to retain cells of different adherence, different suspensibility and different motility. The chamber, which can easily retain and cultivate many types of cells, including high-motility cells and swimming cells, via a series of "speed bumps", readily facilitates cell retention for complex heterogeneous cultures. Yeast cells, red blood cells, rabbit bone marrow aspirate and dinoflagellate swimming cells were introduced into the chip for multi-cell retention, multi-cell culture and observation. Here, we show that the chamber creates a flow field with a ratio of end/start speeds as low as 0.01. The logarithmic distribution of flow-rate within the chamber is controlled precisely by pressure, all of the cell types that we tested were retained easily within the chamber. Many cell-cell interactions were observed, predicting a high potential for the success of on-chip heterogeneous cell experiments.
Assuntos
Técnicas de Cultura de Células/métodos , Técnicas Analíticas Microfluídicas/instrumentação , Animais , Células da Medula Óssea/citologia , Comunicação Celular , Técnicas de Cultura de Células/instrumentação , Células Cultivadas , Galinhas , Dinoflagellida/citologia , Desenho de Equipamento , Eritrócitos/citologia , Técnicas Analíticas Microfluídicas/métodos , Coelhos , Leveduras/citologiaRESUMO
Hepcidin is known to be expressed in fish with bacterial challenge and iron overload. Here we first report the hepcidin expression induced in the developmental stages from embryo to fry of red sea bream (Pagarus major) and in juvenile black porgy (Acanthopagrus schlegelii B.) upon continuous waterborne exposure to BaP. The gene expression of CYP1A1 and IgL (immunoglobulin light chain) were both measured. Expression of the Pagarus major hepcidin gene (PM-hepc) was increased in post hatch fry at 24 h and 120 h exposure to BaP at concentrations of 0.1, 0.5 and 1.0 microg/l, respectively. The gene expression pattern was comparable to that of CYP1A1 but different from that of IgL. In addition, a high number of AS-hepc2 transcripts (Acanthopagrus schlegelii B. hepcidin gene) were detected in the liver upon exposure to 1.0 microg/l BaP. This study demonstrates that hepcidin gene expression is significantly induced in BaP-exposed red sea bream and black porgy.
Assuntos
Peptídeos Catiônicos Antimicrobianos/genética , Benzo(a)pireno/toxicidade , Exposição Ambiental , Regulação da Expressão Gênica/efeitos dos fármacos , Perciformes/fisiologia , Dourada/fisiologia , Poluentes Químicos da Água/toxicidade , Animais , Citocromo P-450 CYP1A1/genética , Regulação da Expressão Gênica no Desenvolvimento/efeitos dos fármacos , Hepcidinas , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Fatores de TempoRESUMO
We examined the influence of macronutrient (nitrate and phosphate) additions on Ni uptake by phytoplankton (Prorocentrum donghaiense and Skeletonema costatum) and its subsequent transfer to marine copepods (Calanus sinicus and Labidocera euchaeta). Ni uptake by phytoplankton after 24h of exposure was markedly dependent on nutrient conditions, with a higher nutrient quota facilitating Ni accumulation in the algae. Trophic transfer was quantified by measurements of the Ni assimilation efficiency in C. sinicus and L. euchaeta, feeding on the algae under different nutrient treatments. Ni assimilation efficiency generally increased with an increase of nutrient concentration in the algae. A significant positive-correlation was found between the Ni assimilation efficiencies of the copepods and the %intracellular Ni in the algal cells. However, ambient nutritional conditions had little effect on the physiological turnover rate constant of Ni by copepods. Thus, nutrient enrichment may lead to an increase in Ni uptake and transfer in marine plankton.
Assuntos
Copépodes/metabolismo , Níquel/farmacocinética , Nitrogênio/metabolismo , Fósforo/metabolismo , Fitoplâncton/metabolismo , Animais , Meios de Cultura , Ingestão de Alimentos/fisiologia , Eutrofização/fisiologia , Nitrogênio/análise , Fósforo/análise , Água do Mar/química , Fatores de TempoRESUMO
Paralytic shellfish toxin (PST) profiles of 16 Alexandrium isolates from the Southeast China Sea were analyzed by high-pressure liquid chromatography. Toxin content and composition of three A. tamarense isolates, ATDH01, ATGX02 and ATMJ02, were also investigated at different growth phases and under various culture conditions. Our results showed that six strains of A. affine were non-toxic, while 10 strains of A. tamarense and A. catenella were toxic. These toxic isolates grown in the same culture conditions consistently produced an unusually high proportion of the N-sulfocarbamoyl toxin C1/2 (around 60-80% of total toxins) and medium amounts of gonyautoxin GTX5 (around 15-30% of total) with only trace quantities (<5% of total) of other saxitoxin derivatives (i.e. GTX1, GTX3, GTX4 and neoSTX). The toxin composition of three A. tamarense isolates did not vary with the growth phases, although higher toxin contents (Qt, fmolcell(-1)) were found in the exponential phase. Variations in temperature, salinity and nutrient levels affected toxin content of three A. tamarense isolates but they did not have pronounced effects on the toxin composition (mole %). These results indicate that toxin composition remained relatively constant under various culture conditions, suggesting that toxin composition could be used as a stable biomarker for the Alexandrium species in this region. However, comparison of toxin profiles between isolates from different localities require special caution since isolates even from the same region can have distinct toxin profiles.
Assuntos
Dinoflagellida/metabolismo , Saxitoxina/química , Animais , Biomarcadores , Cromatografia Líquida de Alta Pressão , Dinoflagellida/genética , Dinoflagellida/crescimento & desenvolvimento , Eucariotos/química , Oceanos e Mares , RNA de Protozoário/análise , Saxitoxina/isolamento & purificação , Especificidade da EspécieRESUMO
The photo-oxidation of Sb(III) to Sb(V) by marine microalgae (diatom, green and red algae) with or without the presence of transition metals (Fe(III), Cu(II) and Mn(II)). The influence of marine phytoplankton on the photochemistry of antimony was confirmed for the first time. The conversion ratio of Sb(III) to Sb(V) increased with increasing algae concentration and irradiation time. Different species of marine phytoplankton were found to have different photo-oxidizing abilities. The photochemical redox of transition metals could induce the species transformation of antimony. After photo-induced oxidation by marine phytoplankton and transition metals, the ratio of Sb(V) to Sb(III) was in the range of 1.07-5.48 for six algae (Tetraselmis levis, Chlorella autotrophica, Nannochloropsis sp., Tetraselmis subcordiformis, Phaeodactylum tricornutum, and Porphyridium purpureum), and only 0.92 for Dunaliella salina. The distribution of antimony in the sunlit surface seawater was greatly affected by combined effects of marine phytoplankton (main contributor) and transition metals; both synergistic and antagonistic effects were observed. The results provided further insights into the distribution of Sb(III) and Sb(V) and the biogeochemical cycle of antimony, and have significant implications for the risk assessment of antimony in the sunlit surface seawater.
Assuntos
Antimônio/metabolismo , Luz , Fitoplâncton/metabolismo , Água do Mar/química , Elementos de Transição/metabolismo , Animais , Antimônio/química , Eucariotos/metabolismo , Oxirredução , Fotoquímica , Fitoplâncton/química , Espectrometria de FluorescênciaRESUMO
The paper aimed to identify the primary of polychlorinated biphenyls(PCBs) in the Jiulong River Estuary, investigate the spatial distribution of PCBs contamination in the environment, localize the atmospheric source and evaluate ongoing PCBs emissions by analyzing soil samples collected along the Jiulong River region. In addition, the accumulation of PCBs in the human food chain was quantified by analyzing leaf of orange trees and vegetable samples collected along a gradient of soil/atmospheric contamination moving away from the source. Consequently, the impact on the human health and the ecosystem was quantified, different management options were proposed to reduce this impact and to carry out research on organic contaminants along the Jiulong River and Xiamen region.
Assuntos
Citrus sinensis , Monitoramento Ambiental/estatística & dados numéricos , Poluição Ambiental/prevenção & controle , Folhas de Planta/química , Bifenilos Policlorados/análise , Poluentes do Solo/análise , Verduras/química , China , Cromatografia Gasosa , Clima , GeografiaRESUMO
The relationship between Alexandrium tamarense (Lebour) Balech, one of red-tide alga, and two strains of marine bacteria, Bacillius megaterium (S7) and B. halmapulus (S10) isolated from Xiamen Western Sea, was investigated by evaluating the growth state of A. tamarense and the variation of beta-glucosidase activity in co-culture system. The results showed the growth and multiplication of the alga were related with the concentration, genus speciality of the bacteria, and growth stage of the alga itself. The growth of A. tamarense was obviously inhibited by S7 and S10 at high concentration. Either inhibition or promotion contributed much more clearly in earlier than in later stage of the growth of the alga. Furthermore, there was a roughly similar variation trend of the activity of extra-cellular enzyme, beta-glucosidase, in the water of the separately co-cultured bacteria S7 and S10 with the alga. The beta-glucosidase activity (beta-GlcA) rapidly increased during the later algal growth accompanying the increase of the lysis of the alga cells. The obvious inhibition of A. tamarense by marine bacteria at high concentration and evident increase of beta-GlcA in co-colture system would help us in better understanding the relationship between red-tide alga and bacteria, and also enlightenedus the possible use of bacteria in the bio-control of red-tide.
Assuntos
Bacillus megaterium/crescimento & desenvolvimento , Dinoflagellida/crescimento & desenvolvimento , Microbiologia da Água , Animais , Bacillus megaterium/enzimologia , Técnicas de Cocultura/métodos , Contagem de Colônia Microbiana , Dinoflagellida/enzimologia , Dinâmica Populacional , Especificidade da Espécie , beta-Glucosidase/metabolismoRESUMO
The concentrations of Cu, Pb, Zn and Cd in surface sediments from Minjiang Estuary-Mazu and Xiamen-Jinmen sea areas of China were investigated during 1995-1996. The concentration ranges of Cu, Pb, Zn and Cd in the Minjiang Estuary-Mazu sea area were 16.4-37.2, 33.4-69.6, 92.1-128, 0.087-0.336 mg/kg(dry wt.), respectively; those for Xiamen-Jinmen sea area were 11.0-24.5, 36. 0-80.3, 77.5-161, 0.135-0.285 mg/kg(dry wt.), respectively. The concentrations and distributions of Cu, Pb, Zn and Cd in surface sediments of Minjiang Estuary-Mazu and Xiamen-Jinmen sea areas were analyzed and evaluated. The results showed that the values of Zn and Pb exceeded those of sediment quality criteria. The average concentration of Cu in Minjiang Estuary-Mazu sea area was higher than that in Xiamen-Jinmen sea area. The obviously higher concentrations of Cu, Pb, Zn and Cd were found at outlets of Minjiang and Jiulong River. From the estuaries to open sea, the concentrations of Cu, Pb, Zn and Cd had a decreasing trend, and then elevated in the sea areas near Mazu and Jinmen, suggesting that Cu, Pb, Zn and Cd in Minjiang Estuary-Mazu and Xiamen-Jinmen sea areas may come from both the mainland and Taiwan of China.
Assuntos
Poluentes Ambientais/análise , Sedimentos Geológicos/química , Metais Pesados/análise , China , Monitoramento AmbientalRESUMO
Dinoflagellates are the major causative agents of harmful algal blooms in the coastal zone, which has resulted in adverse effects on the marine ecosystem and public health, and has become a global concern. Knowledge of cell cycle regulation in proliferating cells is essential for understanding bloom dynamics, and so this study compared the protein profiles of Prorocentrum donghaiense at different cell cycle phases and identified differentially expressed proteins using 2-D fluorescence difference gel electrophoresis combined with MALDI-TOF-TOF mass spectrometry. The results showed that the synchronized cells of P. donghaiense completed a cell cycle within 24 hours and cell division was phased with the diurnal cycle. Comparison of the protein profiles at four cell cycle phases (G1, S, early and late G2/M) showed that 53 protein spots altered significantly in abundance. Among them, 41 were identified to be involved in a variety of biological processes, e.g. cell cycle and division, RNA metabolism, protein and amino acid metabolism, energy and carbon metabolism, oxidation-reduction processes, and ABC transport. The periodic expression of these proteins was critical to maintain the proper order and function of the cell cycle. This study, to our knowledge, for the first time revealed the major biological processes occurring at different cell cycle phases which provided new insights into the mechanisms regulating the cell cycle and growth of dinoflagellates.
Assuntos
Ciclo Celular , Dinoflagellida/citologia , Proteômica , Proteínas de Protozoários/metabolismo , Western Blotting , Dinoflagellida/metabolismo , Eletroforese em Gel Bidimensional/métodos , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por MatrizRESUMO
The mode of action of PAHs that causes fish developmental malformations is unclear. The embryotoxicity of marine medaka (Oryzias melastigma) was investigated after individual exposure to three- to five-ring PAHs Phe, Py, and BaP or co-exposure with α-ANF for 18 days. We found that the relationships between EROD induction and developmental deformities of embryos showed a various pattern under different exposure scenarios of Phe, Py, and BaP, which suggested possibly different modes of action in determining the developmental toxicities. As for co-exposure scenarios of each PAH combined with ANF, it showed potentially synergistic effects. The inhibited CYP1A mediated enzyme activity by ANF after co-exposure did not effectively alleviate developmental toxicity of embryo. It showed potentially synergistic effects after co-exposure of marine fish embryos to CYP1A inhibitors and PAH-type CYP1A inducers. Heart deformities in the early life stages of marine medaka were recommended as a biomarker for indicating the extent of PAH pollution.
Assuntos
Citocromo P-450 CYP1A1/metabolismo , Embrião não Mamífero/efeitos dos fármacos , Hidrocarbonetos Policíclicos Aromáticos/toxicidade , Poluentes Químicos da Água/toxicidade , Animais , Benzo(a)pireno/toxicidade , Citocromo P-450 CYP1A1/antagonistas & inibidores , Relação Dose-Resposta a Droga , Embrião não Mamífero/metabolismo , Oryzias , Fenantrenos/toxicidade , Pirenos/toxicidadeRESUMO
Okadaic acid (OA) is a principal diarrhetic shellfish poisoning toxin produced by marine dinoflagellates. This study compared protein profiles of mice small intestines at four time points (0, 3, 6 and 24 h) after a single oral administration of 750 µg/kg OA, and identified the differentially expressed proteins using 2-D DIGE and MALDI-TOF-TOF mass spectrometry. The results showed that the toxin content of the intestines reached its peak 3h after oral administration and then decreased rapidly. OA remarkably inhibited the intestinal PP activity but it recovered to the normal levels within 6 to 24 h. Electron microscope revealed the collapse of the villous architecture and the intestinal microvilli fell off at 3 h, but were repaired within 24h. Notable damage to the intestinal ultrastructure was observed after oral administration. Comparison of the small intestine protein profiles at four time points revealed that 58 proteins were remarkably altered in abundance, and these proteins were involved in macromolecular metabolism, cytoskeleton reorganization, signal transduction, molecular chaperoning and oxidative stress, suggesting that OA toxicity in mouse intestines was complex and diverse, and that multiple proteins other than PP were involved in the diarrhetic process. Villin 1 and hnRNP F might be the key triggers inducing diarrhea in the mouse small intestines.
Assuntos
Diarreia/metabolismo , Inibidores Enzimáticos/efeitos adversos , Regulação da Expressão Gênica/efeitos dos fármacos , Intestino Delgado/metabolismo , Ácido Okadáico/efeitos adversos , Proteoma/metabolismo , Intoxicação por Frutos do Mar/metabolismo , Animais , Inibidores Enzimáticos/farmacologia , Masculino , Camundongos , Camundongos Endogâmicos ICR , Ácido Okadáico/farmacologia , Proteômica/métodos , Fatores de TempoRESUMO
Alexandrium catenella is a widely spread dinoflagellate species which can produce potent neurotoxins and result in paralytic shellfish poisoning. To date, the molecular mechanisms regulating toxin biosynthesis remain unclear. This study compared protein profiles of a toxicity-lost mutant of A. catenella, ACHK-NT and its wild-type, ACHK-T in the exponential phase, using two dimensional differential gel electrophoresis and MALDI-TOF-TOF mass spectrometry. Morphological analysis showed that both subcultures were morphologically identical with the distinctive taxonomic characteristics of A. catenella. Sequence analyses of ITS1, 5.8S, ITS2 and 18S demonstrated that the mutant and wild subcultures were genetically identical for these markers. 90 differentially expressed protein spots were identified from ACHK-NT, of which 34 were down-regulated and 56 were up-regulated. Using a multilayered strategy for de novo protein sequence analysis, 67 proteins assigned to different functional categories were identified. Among them, 25 involved in bioluminescence, secondary metabolite biosynthesis, protein modification and toxin biosynthesis were down-regulated, while 42 participating in carbon fixation, stress response, transporter and protein folding were up-regulated. This study indicated that the strengthening of certain biological processes coupled with the depression of essential reactions upstream or downstream of the toxin biosynthetic pathway might have blocked toxin production and resulted in the loss of toxicity in the mutant A. catenella.
Assuntos
Dinoflagellida/genética , Toxinas Marinhas/biossíntese , Proteínas/química , Proteômica/métodos , Sequência de Bases , Eletroforese em Gel Bidimensional , Dados de Sequência Molecular , Mutação , Intoxicação por Frutos do Mar , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por MatrizRESUMO
Denitrification is an important process mitigating nitrogen (N) pollution in aquatic systems. Water samples in 13 sites throughout the Jiulong River Estuary were collected in July, 2010 in a preliminary investigation of the denitrification rate in this area. As end-products of denitrification, dissolved N2 was measured by determining N2 : Ar ratios using MIMS (HPR-40), while the concentration of nitrous oxide (N2O) dissolved in water was determined by Purge and Trap-Gas Chromatography. The results showed significant spatial variance of net increase of dissolved N2 (ranging between - 9.9 and 66.8 micromol x L(-1)) and N2O (ranging between 4.3 and 31.5 nmol x L(-1)) in the Jiulong River Estuary. The net increase of dissolved N2 and N2O declined gradually from river sites to sea sites. Dissolved N2O was supersaturated by 170%-562%. The air-water fluxes of N2 ranged between -2.9 and 53.2 mmol x (m2 x d) (-1), and N2O between 5.2 and 23.9 micromol x (m2 x d)(-1). The N2O yield shared only 0.03% - 1.2% (average 0.25%) of total N air-water flux. The results suggested that water temperature and nutrient (N and P) were the key factors influencing denitrification. The denitrification rate is controlled by nitrate level at fresh-water sites with salinity < 0.5%. However, in salty waters, net increase in N2 and N2O mainly originated from denitrification occurring upstream of the estuary, and was dominated by the salinity gradient due to tidal mixing.
Assuntos
Desnitrificação , Estuários , Nitrogênio/química , Poluentes da Água/análise , Poluição da Água/prevenção & controle , China , Água Doce/análise , Nitrogênio/análise , Óxido Nitroso/análise , Rios , Estações do Ano , Água do Mar/análiseRESUMO
Band grouping indices combined with single band characteristic were used to extract urban built-up land based on satellite image in the Jiulong River Watershed. Landscape ecology method and statistical analysis were employed to explore the relationship between urban built-up land and permanganate index, NH4(+) -N, TP concentrations. There were significantly positive correlations between the proportion of urban built-up land and permanganate index, NH4(+) -N, TP (r = 0.701, 0.695, 0.789). It indicates the proportion of urban built-up land areas in the sub-watershed could be an effective indicator of water quality. The largest patch index (LPI) was positively correlated to permanganate index, NH4(+) -N, TP concentrations in the water (r = 0.555, 0.643, 0.722). The landscape shape index(LSI) was positively correlated to permanganate index and TP concentrations in the water (r = 0.564, 0.553). These means the impacts of urban built-up land on water quality are influenced not only by urban built-up land areas but also by spatial patterns. The seasonally linear correlation results show that water quality deteriorates quickly with urban built-up land during the flood season and dry season, and the water is susceptible to eutrophication in both flood and dry seasons. The water quality in most sub-watersheds are impacted by urban built-up land, while the urban built-up land areas of Longmen stream, Su stream and Xiao stream located in headstreams are intensive, which need to be adjusted and controlled to protect the water quality.